1. Field
The following description relates to a directional sound generating technique, and more particularly, to a directional sound generating apparatus and a directional speaker array including the same.
2. Description of the Related Art
Typically, sound generating apparatuses such as loudspeakers output sound without directivity, and the output sound is radiated in all directions. Although sound pressures vary depending on the location of a listener, the sound spreads out widely from the sound generating apparatus. Therefore, those who do not want to hear the sound may inevitably be exposed to it. To avoid such noise pollution or disturbance, one may use headphones or earphones. However, these portable devices may be uncomfortable to wear or move with and may even impair the user's hearing.
Accordingly, technologies have been pursued to enable sound to be transmitted only to a particular listener or a particular area, i.e., a personal sound zone, without the use of additional devices such as earphones or headphones. For example, one technology employs a plurality of sound sources arranged in a line to output sound with different phases such that the directivity of the radiated sound is improved. Another technology employs a hard wall installed behind a sound source to improve sound directivity.
However, in such technologies, severe sound distortion may occur depending on the frequency range. Moreover, to achieve constant directivity over the whole frequency band, signal properties may require additional compensation according to frequency or the sound generating apparatus may need to be increased in size.